<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        var str = 'hello';
        console.log(str.split())    //['hello']
        console.log(str.split(""))  //['h', 'e', 'l', 'l', 'o']
        console.log(str.split("l")) //['he', '', 'o']
    </script>
</body>
</html>